Nitride-based semiconductor light-emitting diode and illuminating device

Abstract

A plurality of semiconductor layers including a light-emitting layer ( 14 ) are formed on the main surface of a substrate ( 10 ) which is composed of a group III-V nitride semiconductor. A first n-type semiconductor layer ( 12 ) containing indium is formed between the light-emitting layer ( 14 ) and the substrate ( 10 ), thereby reducing the affect of damage in the substrate surface. By having such a structure, there is realized a semiconductor light-emitting device having uniform characteristics.

1. A light-emitting diode comprising:
 a substrate made of group III-V nitride semiconductor; 
 a first n-type semiconductor layer containing indium and formed over a main surface of the substrate; 
 a light-emitting layer formed over the first n-type semiconductor layer; 
 a second n-type semiconductor layer formed between the substrate and the first n-type semiconductor layer; 
 a third n-type semiconductor layer formed between the first n-type semiconductor layer and the light-emitting layer; and 
 a fourth n-type semiconductor layer formed between the first n-type semiconductor layer and the light-emitting layer, the fourth n-type semiconductor layer being directly formed on the third n-type semiconductor layer, 
 wherein the third n-type semiconductor layer is a contact layer on which an n-side electrode is formed. 
 
     
     
       2. The diode of  claim 1 ,
 wherein the fourth n-type semiconductor layer is made of a compound whose general formula is represented by Al e Ga 1-e N (0≦e<1). 
 
     
     
       3. The diode of  claim 2 ,
 wherein the fourth n-type semiconductor layer is a cladding layer. 
 
     
     
       4. The diode of  claim 3 ,
 wherein the cladding layer has a thickness of 5 to 200 nm inclusive. 
 
     
     
       5. An illuminating device comprising multiple light-emitting diodes,
 wherein the diodes including: 
 a substrate made of group III-V nitride semiconductor; 
 a first n-type semiconductor layer containing indium and formed over a main surface of the substrate; 
 a light-emitting layer formed over the first n-type semiconductor layer; 
 a second n-type semiconductor layer formed between the substrate and the first n-type semiconductor layer; 
 a third n-type semiconductor layer formed between the first n-type semiconductor layer and the light-emitting layer; and 
 a fourth n-type semiconductor layer formed between the first n-type semiconductor layer and the light-emitting layer, the fourth n-type semiconductor layer being directly formed on the third n-type semiconductor layer, 
 wherein the third n-the semiconductor layer is a contact layer on which an n-side electrode is formed. 
 
     
     
       6. The diode of  claim 1 , wherein the first n-type layer is a monolayer. 
     
     
       7. The illuminating device of  claim 5 , wherein the first n-type layer is a monolayer.